Morning Sickness

Nausea and morning sickness in pregnancy, unlike its name suggests, occurs any time of the day or night. It is common, affecting up to 70 percent of pregnant women, and can be more severe in a first pregnancy.

During the first 14 weeks, morning sickness is caused by elevated levels of certain hormones.

These hormones affect the entire digestive system, causing waves of nausea, vomiting, constipation and gas. Estrogen, in particular, may cause special sensitivity to odors so that mildly offensive smells grow more powerful and even sickening. Nausea and vomiting may also be aggravated by emotional stress and fatigue.

Usually, morning sickness begins at 4 to 8 weeks of gestation and subsides by 14 to 16 weeks. However, some women struggle with nausea and vomiting throughout their entire pregnancy. In rare instances, nausea and vomiting may be so severe that a pregnant woman cannot maintain proper nutrition, which can cause weight loss, dehydration and liver damage, and can even be life-threatening to the mother and/or the fetus if left untreated. This serious condition is known as hyperemesis gravidarum, and it affects about 1 in every 300 pregnant women.